Night-time
by quintessentialy
Summary: Fionna's scared of growing up, but Marshall Lee's lived too long to really be scared of anything. When she turns eighteen and the two begin to grow closer, her fears soon turn into his as well. Will the two be brought closer by this, or will it slowly tear them apart? (More characters to come!)


Thirty-seven minutes past midnight and Fionna was dead asleep. Cake was downstairs, half-asleep and eating some meatloaf, staring at BMO's screen and trying to keep her eyes open. Thirty-eight minutes past midnight and Cake was asleep, face down on the table, and Fionna's window was opening. Thirty-nine minutes past midnight and Marshall Lee was slipping into the bedroom, closing the window behind him and sauntering over to the bed.

"Fionna." He whispered, hissing in the slightest, "Fionna! Wake up!" He kneeled down next to the bed, pressing his face close to hers, " _Fionna!_ "

She opened her eyes and gasped, wriggling around in her cocoon-like sleeping bag, removing her arms and shoving Marshall away, hard. He put his hands back and caught himself, rolling his eyes and floating into the air, "Geez, Marshall! What is your _problem_?" Fionna snapped, slipping out of the cocoon, wrapping her arms around herself.

"Oh my glob, are those your pajamas?" Marshall snickered, staring at her red onesie. She blushed and grabbed a blanket, wrapping it around herself, "Fionna, you are _such_ a dweeb."

"Why are you here? Can't you seem I'm trying to – to sleep? I had a hard day." She mumbled, exasperated. She still felt horribly drowsy. "I just want to rest."

"Oh! I've got something to show you. Trust me, it's worth staying up for." Marshall grinned at her, flashing his fangs in her direction. She grimaced and sat down on the bed, pursing her lips.

"Really? Something that couldn't wait until morning?"

"No way. Trust me, it is uh-maze-ing." Marshall smirked, landing on the ground, feet-first. Fionna stared at him for a moment before huffing, leaning over and grabbing her backpack from beside the bed.

"Fine, but I'm not changing. We're going to go and then you're going to bring me back so I can get the sleep a hero like me deserves." She muttered, dropping the blanket and slipping the backpack on.

"A hero, huh? Full of yourself much?" Marshall teased her, and she rolled her eyes.

"Oh, shut up. Let's go."

He took her hand and helped her out the window, taking her other one and pulling her into the sky. She dangled underneath him, watching Aaa pass by under her feet. She stared at the faraway Candy Kingdon, lit up even in the middle of the night. They passed by it, headed to the caves. Inside the caves and past Marshall's house, they stopped near the ocean. He set her down and then tugged her over to some of the small tidal pools, settled in between the rock of the cave and the border of the ocean, mixed in the mud and sand.

"Okay, are you looking?" He asked her, glancing up. Fionna had settled herself on top of a large rock to keep her pajamas from getting messy.

"I'm watching."

"Are you _really_ looking?"

"Marshall!" Fionna whined, yawning and brushing her bangs out of her face, "Get on with it! It's _late_."

Marshall stared at her for a moment before clapping. The tidal pools lit up with colors, small creatures swimming around inside of them. Weird fish, some snails – all lit up in fantastic, neon color. Marshall sat down beside Fionna, wrapping an arm around her shoulders as she gaped at the creatures.

"See? Pretty cool, right?" He grinned toothily, and she grinned and glanced at him before leaning down, dipping her finger into the water. She plucked one of the snails out of the mud and let it slip around on her hand, bright pink.

" _So_ cool. How'd you figure this out?" She asked, grabbing his hand so the snail could crawl from hers to his.

"I was out here trying to record. I know the acoustics are _so_ much better in my house, but I wanted that wave background noise. I started clapping to make a beat and then _BAM_ , crazy awesome neon sea creature party. I thought it might interest you."

"I wonder why they light up," Fionna mumbled, taking the snail from Marshall's hand and setting it back in the water.

"Probably one of Prince Gumball's experiments." Marshall shrugged, and Fionna glanced over at Marshall.

"You think he did this?" She asked, trying not to grimace.

"Yeah. He's always doin' the science over in his castle, you know that. Why are you making that face? Do you have beef with Gumball?"

"Beef? No, we don't cook together often."

"Oh my _glob_ , Fionna, do you have a problem with him?" Marshall laughed, pulling his arm away from her and reaching for his bass settled on one of the rocks among some other recording equipment.

"Well, no. Yes. No. Kind of. Not really – Yes. Yes." She huffed, setting her face in her hands, "I think he sees me like a little kid."

"You are a little kid!" Marshall smirked, plucking at the strings of his bass. Fionna groaned and hit Marshall's shoulder, scooting away from him to lean her back against the side of the cave.

"I'm not! I'm nearly eighteen."

"Nearly eighteen? Dang, Fionna, you're getting _old_." Marshall teased her, chuckling, "And you still wear onesies."

"Shut up, okay! I'm human, you know, so I only live to be like – eighty. I'm nearly through a fifth of my life, then, right?"

"I think you mean a fourth."

"What?!" She gasped, throwing her hands up into the air, "Dude, I am so bad at math! I have less time than I thought!" She yelled, burying her face in her hands, "I'm almost adult-ish and everyone keeps treating me like a kid. By the time they start treating me like a grown-up, I'll be _dead_!"

"Fionna, cool it. That's not true." Marshall frowned, reaching over to swat her hands away from her face, "You're not dying anytime soon, got it? You've still got tons of years. If it makes you feel any better, I'll start treating you like a ten-year-old instead of a five-year-old." He laughed slightly, and Fionna pouted.

Marshall sighed and continued, "Fine. I'll start treating you like you're seventeen. Which is really nothing compared to my one thousand years _plus_ of experience, but whatever."

"Thank you. At least one of my friends will treat me a bit better." She mumbled, crossing her arms and glancing back at the tidal pools. After a moment of bass-strumming and wave noise, Fionna spoke again, "Thanks for showing me this."

"You're welcome. You still tired?"

"Yeah."

"You want me to take you home?" He asked, glancing up. She glanced at him and she met his gaze. She opened her mouth to say something before shaking her head and closing it.

"I'll let myself have a couple more minutes." She replied, and he nodded, continuing on strumming his bass. She closed her eyes for a moment and he continued to strum, glancing between her and the tidepools the entire time.

The sun started to come up and he realized she'd fallen asleep, and in a rush, slung her over his shoulder and flew her back to the treehouse as quickly as he could. She snored the entire way, even when he tucked her back into her sleeping bag. "Night, Fionna." He mumbled, pausing for a moment before shaking his head and sauntering back to the window, slipping out just as easily as he had come in.


End file.
